The present invention relates to an image forming apparatus which can adjust image forming conditions based on reading results of reference original.
For successful reproduction of images, an image forming apparatus such as a copying machine conventionally requires various settings and adjustments. Factors to be set or adjusted include, for example, light intensity of a tungsten halogen lamp, density of reproduced images, life-size magnification, and relative position of a reproduced image with respect to copy paper. These settings and adjustments are performed not only by factory workers during production of image forming apparatuses but also by service personnel whenever required in the field.
In carrying out most of these settings and adjustments, an operator has to make estimates of adjustment values for individual adjustment points based on a reproduced image of a reference original sheet. It is to be noted that these operations are largely guesswork using the trial-and-error method and, therefore, they are time-consuming and require factory workers and field technicians to have sufficient skill to do the job. This fact has so far been a sort of obstacle to improving the working efficiency.
Recently, there have been various approaches for automating the adjustments of image forming apparatuses. In one of such approaches, an image forming apparatus is provided with an optical sensing device on a paper path for reading a reproduced image of a reference original sheet. Based on information derived from reading the reproduced image, the apparatus performs automatic adjustments of image forming conditions, e.g., alteration of set values for specified adjustment points.
It is however a common practice to use a dedicated reference original sheet for each process of the above-mentioned adjustments. Even in the image forming apparatus which performs automatic adjustments, an operator has to manually place dedicated reference original sheets one after another for individual adjustment items. In case the image forming apparatus requires several adjustment processes, it is inevitable to prepare a plurality of reference original sheets and place an appropriate one on an original placement plate prior to each adjustment process. It would be understood that storage and handling of different reference original sheets are cumbersome, especially for service personnel who are required to always carry those reference original sheets with them. This is still far from perfection in automation of the adjustment processes.
Under these circumstances, it is desirable to devise an image forming apparatus which can fully automate a greater part of the adjustment processes, eliminating the need for storing and carrying reference original sheets.